1. Field of the Invention
This invention relates to internal climate control for aircraft.
2. Description of Prior Art
The prior art relating to internal aircraft conditions, and the control thereof, is well documented in aviation medical journals, aviation engineering journals, government aviation regulations and popular aviation magazines. One publication of particular interest addressing the basic principles and the existing prior art in the field is "Fundamentals of Aircraft Environmental Control" by Alvin Ebeling (1968) Hayden Book Co., Inc. New York. The forgoing literature is readily available and the material disclosed is incorporated herein by reference.
One principal problem pertaining to aircraft climate control, especially on recent aircraft designs, is the loss of moisture inside the aircraft during flight. Prior to the advent of commercial jet aviation, the problem of retaining moisture on aircraft was less pronounced than it is today. The principal method of maintaining acceptable moisture levels was by means of a boiler system, whereby water is evaporated into the internal ambient air. Excess water is carried on board for this specific purpose. This has proved only marginally effective. Another system presently in use sprays a very fine water mist at ambient temperatures into the cockpit and cabin area, the water source being the limited on-board supply of potable water.
While the aircraft itself may carry sufficient water to humidify the cabin air through the entire voyage, such a procedure would necessarily entail loading large amounts of water onto the aircraft, thus adding substantially to its weight. The additional weight of the aircraft quite obviously increases its fuel consumption and reduces available commercial space on said aircraft.
On the jet propelled commercial passenger aircraft of today, flight durations range from less than one and up to fourteen hours primarily at flight levels from 18,000 feet to 40,000 feet, and in some instances, as high as 50,000 feet. The maximum possible moisture content in the ambient air at these altitudes is less than 1/20th that of ambient air of sea level.
On an average wide body aircraft today the entire air supply is exchanged approximately every three minutes. Among other methods, this involves the extraction of air from the engine area, heating it and, in most cases, cooling it prior to entering it into the internal structure of the aircraft, while simultaneously exhausting an appropriate supply, thus maintaining desired pressure and temperature.
Owing to the arid nature of this air, internal moisture is rapidly depleted. As countless millions of passengers, thousands of flight attendants and flight deck personnel are aware, this is a frequently troublesome situation. The lack of resolution to this troublesome situation is apparent in the continued discomfort still experienced by these people at the time of this writing. Not only does it, at the time, cause considerable inconvenience through irritation of the mucous membranes but it also affects the skin and, in addition, aggravates certain existing medical or health problems. In addition, owing to the temporary, in some cases prolonged, dehydration and incapacitation of mucous membranes and other tissues and follicles, it occasionally renders the people subjected to a host of harmful bacteria which they, under normal conditions, would have adequate defense mechanisms for, but under these circumstances, these defenses are severely impaired. It is ironic that all these problems and discomforts which have plagued millions of people for many years should have a simple solution.
It is thus a principal object of the invention to provide desirable moisture content to the air in the internal structure of the aircraft.
There appears to be several reasons for the current substandard climate conditions on high performance commercial jet aircraft. Adequate solutions may have eluded laymen as well as experts, because it is not obvious that when one encounters the arid climate condition on the aircraft, one would associate this with the use of a dehumidification system.
It has, therefore, been left up to the persons on board to provide part of the moisture content by means of natural evaporation from the body, and, in addition, certain materials and fixtures on board the aircraft to maintain moisture in the aircraft for a certain time, thus to a small measure, reducing the problem.